Black water tank overflow

[Hwy Junky]

So DW and I are concerned over what happened this morning in our Itasca Ellipse 42QD. Our unit has 1-1/2 baths with the half bath having its our commode and wash basin.

The sensors on both our black and grey water tanks are questionable so we always have a little concern about our water levels.Today, when I flushed the commode in the 1/2 bath, the tank evidently being full the water backed up into the 1/2 bath water basin. Black water backed up in what I assumed was a grey water basin..

I thought both black and grey were closed systems so how could black water get into grey system??

[bduemig]

I had a motor home several years ago that had the bathroom sink draining into the black tank. My assumption was that a tech in the factory didn't hook it up properly.

But they should be separated. Commode to black tank. Sinks and shower to grey tank.

[GrantR]

I can’t imagine how that would happen if everything is working normally, The black tanks should not be connected to the grey at all unless you had the dump gates open at the drain and the cap on.
I am following though as I have a JD and I expect that they are the same from that perspective.

[Ray,IN]

Some MH's are built that way on purpose. Check your specific plumbing drawings in the Winnebago links at the top of this forum.

[twinboat]

My Thor bath sink drains into the black tank.

I think it's more common then you would think.

[tderonne]

Quite common, as others have said.

I'm more interested in how water went uphill from the toilet to the sink. Gravity doesn't do that. Not a gravity flush toilet then?

[twinboat]

Originally Posted by tderonne

Quite common, as others have said.

I'm more interested in how water went uphill from the toilet to the sink. Gravity doesn't do that. Not a gravity flush toilet then?

Second toilet most likely electric pump flush.

[chuckftboy]

The Ellipse 42 QD, Tour 42 QD and my Horizon 42Q all have the 1/2 bath sink that drains to the black tank. Strange that your macerator pump would work with a full tank. When my tank is full, my pump won't run. Mine shows a green light until 3/4 full, then yellow until full then red and it no longer flushes.

[Mudfrog]

Originally Posted by Hwy Junky

So DW and I are concerned over what happened this morning in our Itasca Ellipse 42QD. Our unit has 1-1/2 baths with the half bath having its our commode and wash basin.

The sensors on both our black and grey water tanks are questionable so we always have a little concern about our water levels.Today, when I flushed the commode in the 1/2 bath, the tank evidently being full the water backed up into the 1/2 bath water basin. Black water backed up in what I assumed was a grey water basin..

I thought both black and grey were closed systems so how could black water get into grey system??

Confused here as to how the water came up through the sink drain that's mounted higher than the toilet? I wouldn't think you could flush without water backing up in the toilet bowl first.

As far as bath sink draining into black tank, ours does that. It's helpful as it gives us an extra day or two on the gray before having to empty.

[GrantR]

I have a 42JD and got home from a long weekend trip today. I dumped when I got home and tested this. The sink in my 1/2 bath definitely drains into the forward grey tank along with the kitchen sink. It may be different for the QD, I did review the plumbing diagram for the JD and it certainly looked like that.

[Ron Postma]

The 42QD 1/2 bath sink drains into the black tank. That is the way it is designed. As stated in an earlier post if the tank sensors associated with the Tecma toilets are working properly the red light should have been on stopping the toilet from flushing. There are separate sensors on the black tank for each toilet. When this happened to you HWY JUNKY were you hooked up to sewer? I have for the past 6 years kept both my grey and black tank valves open whenever hooked up to sewer and I have never had any issues. The Tecma flush provides plenty of water to clear the back tank. When I leave a site I put about 10 gallons of water in both tanks. I then let the driving action clean them.

[RTrider]

For a "remote" 1/2 bath it makes sense to drain the sink to black water - less plumbing for a small amount of water. On the other hand my '14 38Q dumps the washing machine into the black water tank. In my opinion, that is unacceptable, but it is that way it was designed at the factory. We have stayed several places that will let you dump gray water at the site, but not black water. The only "help" is the black water tank is quite large - 75 gal. so a load or two can be done on a short stay without having to pull out just to dump. Of course you can take clothes to the laundry, but that's not why we bought a motorhome with a washer/dryer.

[TXiceman]

Often, a bathroom sink is plumbed to the black tank to get more water in the black tank. Many folks are guilty of not enough water in the black tank.

For you folks that say EWEEEE, at the sink to the black tank. Look at your home. the sinks and bathtub all drain to the same sewer line as the toilet. If you are on a septic system, they all go to the first septic tank in a common line.

Ken

[NeilV]

Originally Posted by TXiceman

Often, a bathroom sink is plumbed to the black tank to get more water in the black tank. Many folks are guilty of not enough water in the black tank.

For you folks that say EWEEEE, at the sink to the black tank. Look at your home. the sinks and bathtub all drain to the same sewer line as the toilet. If you are on a septic system, they all go to the first septic tank in a common line.

Ken

And if your on city sewerage living in a home or an apartment since all the drains are to one system, what backs up in your kitchen sink can be from a toilet a floor or so above you or from a toilet in a home up the street at a higher elevation as many cities have outlawed back flow valves on a homes city sewer connection. This is why there are traps to block the flow of odors at each drain otherwise your kitchen, shower, etc would be pretty ripe with black water odors.

At least in your RV or with a home septic tank you have the small comfort of knowing where it all came from.